Electrode attachment



E. w. RlcKMEYER .2,414,897

ELECTEODE ATTACHMENT Jan. 28, 1947.

Filed Oct. 26, 1945 Patented Jan. y28, 1947 ELECTRODE ATTACHMENT Ernst Walter Rickmeyer, Berkeley, nl., assigner to Jefferson Electric Company, Bellwood, Ill., a corporation ot Illinois Application October 26, 1945, Serial No. 624.791

(CL 20G-152) 8 Claims. l

The present invention relates to a novel terminal wire connection to a center contact member of a mercury switch.

In this type of switch an envelope or shell is provided with two chambers separated by a partition or dividing wall that is provided with a passage or passages .through which mercury is allowed to flow in moving from one chamber to the other. The rate of flow through this dividing wall is controlled so as to provide a denite predetermined time delay in the operation of the switch. While the mercury is disposed in one of the chambers, it bridges or closes an electrical circuit through the switch. As the mercury flows through the dividing wall into the second chamber, the electrical circuit through the switch is broken after a predetermined amount of mercury has left the first chamber. One of the electrical elements making up the circuit through the mercury switch is a center contact member or electrode that passes through the wall of the switch envelope or shell and projects into the mercury that is disposed in the first chamber. envelope may constitutelthe other electrical contact so that the mercury in the first chamber may serve as the electrical connection between the center contact member and the shell wall. In this instance the center contact member must be insulated from the envelope in all respects except through the mercury. Such a mercury switch is placed in an electrical circuit by attaching a terminal wire to the central contact member and a second terminal wire to the switch envelope. The present invention is concerned with the attachment of the terminal wire to the center contact member. It is an object of the invention to provide such Y a connection that makes good electrical contactwlth the center electrode so as to provide very low resistance to the flow oi' electrical current from the terminal vwire to the center contact member. It is lntended that this be accomplished in a relatively simple manner and in a manner that is readily adaptable to mass production. Ease of assembly is an advantage of the present invention and the connection thus produced assures a completely assembled switch that is well sealed. Y

The foregoing constitutes some of the principal objects and advantages of the present. invention others of which will become apparent from the following description and the drawing, in which Fig. 1 is a vertical sectional view taken through a completely assembled mercury switch embodying the present invention;

Fig. 2 is a top plan view o! the mercury switch shown in Fig. 1;

Fig. 3 -is an enlarged fragmentary sectional view showing one embodiment oi' the invention wherein the terminal wire is disposed adjacent 'I'he wall of the shell or switch to one side o! the crimped over portion of the Acenter contact; and

Fig. 4 is a view corresponding to Fig. 3 but showing a modified form of the invention.

For purposes .of illustration, two embodiments of the invention are shown and will be described. It is recognized, however, that many modifications maybe made in these embodiments without departing from the intended scope of the invention.

Referring to the drawing the invention is shown embodied in a mercury switch that comprises a switch envelope or shell III that is of more or less uniform diameter throughout its upper portion and has a smaller diameter at its lower portion so as to provide a shoulder indicated'at Il. A- cup I2 is adapted to rest on this shoulder II and the bottom of this cup forms a dividing wall or partition separating the shell Ill into two chambers I3 and Il. This cup I2 may be made of sintered metal particles ofnickel or like material so that the voids between the particles will provide passages through which mercury and air may pass.

As shown in Fig. l the cup I2 terminates below the upper end of the shell I0. A center contact member I5 projects through the open end of the shell l0 into the chamber I3. This contact member I5 is provided with a shoulder portion I6 and sealing members generally indicated at I1 are mounted concentrically around the center contactl member I5 and are adapted to rest on the upper edge of the cup I2. The shell I0 is crimped over onto the insulating members I1 as shown at I8.

For purposes of illustration, the sealing member I1 comprises a pair of washers I8 and 20 of Bakelite having sandwiched therebetween a rubber gasket 2l. The crimped over portion I8 of the shell I0 firmly holds the sealing elements IB against the top of cup I2 to form aneiective seal.

Mounted on vtop of the sealing members I1 is a copper cup '22 that is disposed concentrically about the center contact member Il and initially projects upwardly as indicated by the broken lines 22a. A metal washer 23 of good electrical conductivity is dropped into the bottom of the copper cup 22 over the upstanding end indicated at broken lines at 24a of the center contact member IB. The end 24a of the center contact member I5 is then crimped over as shown in solid lines at 2l firmly against the metal washer 23. It is to be noted that the length of the crimped over portion Il of center contact member Il is such that it lies within the vertical pro- Jection of the shoulder Il.

Referring to Fig'. 2 it can be seen that the terminal wire 2l is provided at itsiree end with a loop 2l. Referring to Figs. l and 3 this looped 25 to pass throughA the wall of the copper cup.

The upstanding walls 22a of the copper cup 22 are now crimped over as shown in solid lines -at 22h at Fig. 1 to hold the loopedpcrtion 26A of the terminal wire 25 firmly against the metal' wire 23 and preferably against the crimped over portion 24 of center contact member I5.

A modified 4form of the invention is illustrated in. Fig. 3 where the looped portion 26 of the terminal wire 25ls' disposed on top oi the crimped over portion' 24 "o'f center. contact-member i5 and in thisinstancethe. crimped over portion 22h of copper cup 22'holdsja terminal wire firmly against theV looped over' portion 24 of the center contact member,"

Having thus described my invention, what I claim as new and desire 'to secure by Letters Patent is: 'y

l. In a mercury switch having a switch en velope open at one end, a central contact member projecting into the envelope through the open end, a closure for said Aopenencl including means electrically insulating the contact member from the envelope walls,fan electrical conducting cup mounted 4on vtop .of the closure; and electrically engaging the. contact. member, ,a `terminal vwire looped in said cup and projecting .outvvardliv thereof, the top of the' central contact member being crimped over so as to rigidly `holdA the cup against the top closurerof the envelope, and the top of the cup being crimped over the looped terminal wire to firmly secure the wire in place.

2. In` a mercury switch having a switch envelope open at one end, a central Contact member projecting into the envelope through the open a closure for said open end including means electrically insulating the contact member from the envelope walls, an electrical conducting cup mounted on top of the closure and electrically engaging the contact member, the' top of the central contact member being crimped over so as to rigidly hold the cup against the top closure of the envelope, a terminal wire looped in said cup and in electrical' contact-'with the crimped over portion of the central c'ontal'ztv member, 'and the'top of the cup being crimped over the looped terminal wire to firmly secure the wire in place.

3. In a mercury -switchyhaving a switch envelope open at one fend', e.v central contact member projecting into the envelope through the open end, a closure for said open end including means electrically insulating the contact member engaging the contact membenthe top of the central contact member lbeing crimpedover so as to rigidly hold the cup against the top closure of the envelope, a terminalwire looped in said lcup and disposed on top.A of the crimped over portion of the central contact member, and the top ofthe cup being crimped over the looped terminal wireato rmly secure the wire in place.

from the envelope Wal-15,! an electrical'conducting cup mounted on top of ,the Y,closure .and electrically engaging the ,Contact mem-ber, the ltop oi the central contactfmember-being crimped over so as to rigidly hold the cup against' the top closurel of the envelope av terminal Wire 'looped 5. In a mercury switch having a switch envelope open at one end, a central contact member projecting into the envelope through'vthe open end, a, closure for saideopen en'd includingmeans electrically insulating the contact member from the envelope walls, an electricalconducting cup mounted on top of the closure and electricallyengaging the contact member, the topof the cen' tral contact member being crimped over 'so as to rigidly hold the cup against the top closure of the envelope, a terminal wire projecting into saidA I cup and disp'osed adjacentto the 'crimped over portion of the central contact member, and the top of the cup being crimped over the looped terminal wire tormly secure the wire in place.

6. In a mercury switch having a switch enve-` lope open at one end, a central contact member projecting into the envelope through the open end, a closure for said open end including means electrically insulating the contact member from the envelope walls, an electrical conducting cup mounted on top of the closure and electrically engaging the contact member, the top of the central contact member being crimped over so as to rigidly hold the cup against the top closure of the envelope, a terminal wire projecting into said cup and disposed on top of the crimpedover portion of the central contact member, and the top of the cup being crimped over the looped terminal Wire to n rmly secure the Wire in place.

7. In a mercury switch having a switch `envelope open at one end, a central contact member projecting into the envelope through the open end, a closure for said open end including means electrically insulating the contact member from the envelope walls. an electrical conducting cup mounted on top 0i' the closure and electrically engaging the contact member, means at the bottom of the cup on the inside thereof providing a relatively large surface contact with the central contact member, the top of the central contact member being crimped over against said means, a terminal wire disposed on said-means and adjacent to the crimped over portion of the central contact member, and the top of the cup being crimped over the terminal wire.

8. In a mercury switch having a switch envelope open at one end, a centralcontact member projecting into the envelope through the open end,

.. a closure for said open endincluding means elecin said cup and disposed-adjacentto the'crimpedv I over portion of the centralfcontact member and:

the top of the cup being/crimped over/ the looped terminal wire to firmly secure the wire in' place.

4. In a mercury switcnhaving-aswitch envelope open'at one end, a central contact member projecting into the envelope through the open end, a closure for said open end including means electrically insulating the contact member from the envelope walls, an electrical conducting cup mounted on top of the closure and, electrically trically insulating the contact member from the envelope walls, an electrical conducting cup mounted on top of the closure and electrically engaging the contact member, ametallic washer at thebottom of the cup, a terminal wire disposed in the cup against the washer and projecting outwardly thereof, the top of the central 'contact member being crimped overso as to rigidly hold the cup against the top closure of the envelope, and the top of the cup being crimped over the looped terminal wire to ilrmly secure the wire in place.

" ERNST WALTER RICKMEYER. 

